javaWeb实现登录注册的增删改查功能
1.包结构
2.数据库表字段
数据库名：MyDB
表名：acca
字段： id int
name varchar（64）
pwd varchar（64）
3.工具类DBUtil
public class DBUtil {
public static Connection getConn() {
String url="jdbc:sqlserver://localhost:1433;databaseName=MyDB";
String user="sa";//数据库登录名
String pwd="1";//数据库登录密码
Connection conn=null;
try {
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
conn=DriverManager.getConnection(url, user, pwd);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
public static void closeConn(Connection conn,PreparedStatement ps,ResultSet rs) {
try {
if(conn!=null){
conn.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if(ps!=null){
ps.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
if(rs!=null){
rs.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
4.1登录
<style type="text/css">
.input1 {
border: 1px solid #CDC28D; /* 输入框表框颜色*/
background-color: #F2F9FD; /* 输入框背景颜色*/
height:40px; /*输入框高度*/
width: 200px; /*输入框宽度*/
padding-top: 4px; /*输入框里的文字和输入框上边之间的距离
font-family: Arial, Helvetica, sans-serif; /*输入框文字类型*/
font-size: 12px; /*输入框内文字大小*/
padding-left: 10px; /*输入框里的文字和输入框左边之间的距离*/
}
.input2 {
border: 1px solid #1E1E1E; /* 输入框表框颜色*/
background-color: #F2F9FD; /* 输入框背景颜色*/
height: 30px; /*输入框高度*/
width: 80px; /*输入框宽度*/
}
</style>
<body>
<form action="index" method="post">
<table align="center">
<tr height="150dp">
<td></td>
</tr>
<tr align="center">
<td colspan="2"><h1>用户登录</h1></td>
</tr>
<tr>
<td>用户名：</td>
<td><input class="input1" type="text" name="name" /></td>
</tr>
<tr>
<td>密码：</td>
<td><input class="input1" type="password" name="pwd" /></td>
</tr>
<tr align="center">
<td colspan="2"><input class="input2" type="submit" value="登录" /></td>
</tr>
<tr align="right">
<td colspan="2"><a href="register.jsp">注册</a></td>
</tr>
</table>
</form>
</body>
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//执行dopost方法
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//乱码问题的处理
response.setContentType("text/html;charset=utf-8");
request.setCharacterEncoding("utf-8");
//接受前端传递进来的用户名和密码
String name=request.getParameter("name");
String pwd=request.getParameter("pwd");
//数据库的操作
Connection conn=DBUtil.getConn();
String sql="select * from acca where name=? and pwd=?";
PreparedStatement ps=null;
ResultSet rs=null;
//定义一个flag，默认为false
boolean flag=false;
try{
ps=conn.prepareStatement(sql);
ps.setString(1, name);
ps.setString(2, pwd);
rs=ps.executeQuery();
if(rs.next()){
flag=true;//如果存在
}else{
flag=false;//如果不存在
}
}catch (SQLException e) {
e.printStackTrace();
}finally{
DBUtil.closeConn(conn,ps,rs);
}
if(flag){
//如果存在，则重定向到我们要访问的Servlet
response.sendRedirect("UserListServlet");
}else{
//不存在，则返回登录页
response.sendRedirect("index.jsp");
}
}
4.2注册
<style type="text/css">
.input1 {
border: 1px solid #CDC28D; /* 输入框表框颜色*/
background-color: #F2F9FD; /* 输入框背景颜色*/
height:40px; /*输入框高度*/
width: 200px; /*输入框宽度*/
padding-top: 4px; /*输入框里的文字和输入框上边之间的距离
font-family: Arial, Helvetica, sans-serif; /*输入框文字类型*/
font-size: 12px; /*输入框内文字大小*/
padding-left: 10px; /*输入框里的文字和输入框左边之间的距离*/
}
.input2 {
border: 1px solid #1E1E1E; /* 输入框表框颜色*/
background-color: #F2F9FD; /* 输入框背景颜色*/
height: 30px; /*输入框高度*/
width: 80px; /*输入框宽度*/
}
</style>
<body>
<form action="register" method="post">
<table align="center">
<tr height="150dp">
<td></td>
</tr>
<tr align="center">
<td colspan="2"><h1>用户注册</h1></td>
</tr>
<tr>
<td>用户名：</td>
<td><input class="input1" type="text" name="name" /></td>
</tr>
<tr>
<td>密码：</td>
<td><input class="input1" type="password" name="pwd" /></td>
</tr>
<tr align="center">
<td colspan="2"><input class="input2" type="submit" value="注册" /></td>
</tr>
</table>
</form>
</body>
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//执行dopost方法
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
request.setCharacterEncoding("utf-8");
//接收到的注册内容
String name=request.getParameter("name");
String pwd=request.getParameter("pwd");
//判断是否为空，这里可以在前端部分加上正则表达式
if(name!=null && !"".equals(name) && pwd!=null && !"".equals(pwd)){
Connection conn=DBUtil.getConn();
PreparedStatement ps=null;
ResultSet rs=null;
//数据库插入
String sql="insert into acca (name,pwd) values (?,?)";
try{
ps=conn.prepareStatement(sql);
ps.setString(1, name);
ps.setString(2, pwd);
int r=ps.executeUpdate();
if(r>0){
//如果数据库插入成功，则跳转到登录页面
response.sendRedirect("index.jsp");
}else{
//否则注册失败，返回注册页面
response.sendRedirect("register.jsp");
}
}catch (SQLException e) {
e.printStackTrace();
}finally{
DBUtil.closeConn(conn, ps, rs);
}
}else{
//传入数据为空，注册失败
response.sendRedirect("register.jsp");
}
}
4.3查询输出数据库内容
been类
public class User {
private Integer id;
private String name;
private String pwd;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPwd() {
return pwd;
}
public void setPwd(String pwd) {
this.pwd = pwd;
}
public User(Integer id,String name,String pwd){
super();
this.id=id;
this.name=name;
this.pwd=pwd;
}
public User() {
super();
}
}
4.1中登录成功后，首先访问一个Servlet，在这个Servlet中将表中的数据查询，再传递到登录成功后的页面输出显示
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
request.setCharacterEncoding("utf-8");
Connection conn=DBUtil.getConn();
PreparedStatement ps=null;
ResultSet rs=null;
String sql="select * from acca";
List<User> users=new ArrayList<User>();
try{
ps=conn.prepareStatement(sql);
rs=ps.executeQuery();
while(rs.next()){
//循环我们查询的表
User user=new User(rs.getInt(1),rs.getString(2),rs.getString(3));
users.add(user);//将数据装入users
}
}catch (Exception e) {
e.printStackTrace();
}finally{
DBUtil.closeConn(conn, ps, rs);
}
HttpSession session=request.getSession();//建立一个session
session.setAttribute("userList", users);
response.sendRedirect("login.jsp");//登录后的页面
}
}
<body>
<table border="1" cellspacing="0" align="center" width="1000dp"
height="500dp">
<thead>
<tr>
<td>
编号
</td>
<td>
姓名
</td>
<td>
密码
</td>
<td>
操作
</td>
</tr>
</thead>
<tbody>
<%
List<User> users = (List) session.getAttribute("userList");
for (User user : users) {
%>
<tr>
<td><%=user.getId()%></td>
<td><%=user.getName()%></td>
<td><%=user.getPwd()%></td>
<td> //获取到要删除的数据的id，并将数据传输到一个servlet
<a href="deleteServlet?id=<%=user.getId() %>">删除</a>
//获取到要更新的数据的id，并将数据传输到一个servlet
<a href="updateShowServlet?id=<%=user.getId() %>">更新</a>
</td>
</tr>
<%
}
%>
</tbody>
</table>
</body>
显示结果如下，可对页面进行更新或者删除操作
4.4删除数据
在4.3中，登录成功显示页面，将获取到要删除的数据的id传到servlet
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
request.setCharacterEncoding("utf-8");
//接受到将要删除的id
String id = request.getParameter("id");
Connection conn=DBUtil.getConn();
PreparedStatement ps=null;
ResultSet rs=null;
String sql="delete acca where id = ?";
try{
ps=conn.prepareStatement(sql);
ps.setString(1, id);
int r=ps.executeUpdate();
if(r>0){
//不论删除成功还是失败都会返回到登录成功时的servlet，通过该servlet进入登录成功页面
response.sendRedirect("UserListServlet");
}else{
response.sendRedirect("UserListServlet");
}
}catch (SQLException e) {
e.printStackTrace();
}finally{
DBUtil.closeConn(conn, ps, rs);
}
}
4.5数据库更新 修改
4.3中登录成功页面，在点击更新时，页面会先获取到要删除的数据的id，发送给一个servlet进行处理。
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
String id = request.getParameter("id");
//获取要删除数据的id
Connection conn=DBUtil.getConn();
String sql="select * from acca where id=?";//查询出该id的所有字段内容
PreparedStatement ps=null;
ResultSet rs=null;
try{
ps=conn.prepareStatement(sql);
ps.setString(1, id);
rs=ps.executeQuery();
if(rs.next()){
request.setAttribute("id", rs.getInt(1));
request.setAttribute("name", rs.getString(2));
request.setAttribute("pwd", rs.getString(3));
/*
*将数据发送到一个jsp页面，在该页面进行人工的数据的修改
*/
request.getRequestDispatcher("update.jsp").forward(request, response);
}
}catch (SQLException e) {
e.printStackTrace();
}finally{
DBUtil.closeConn(conn,ps,rs);
}
}
<style type="text/css">
.input1 {
border: 1px solid #CDC28D; /* 输入框表框颜色*/
background-color: #F2F9FD; /* 输入框背景颜色*/
height:40px; /*输入框高度*/
width: 200px; /*输入框宽度*/
padding-top: 4px; /*输入框里的文字和输入框上边之间的距离
font-family: Arial, Helvetica, sans-serif; /*输入框文字类型*/
font-size: 12px; /*输入框内文字大小*/
padding-left: 10px; /*输入框里的文字和输入框左边之间的距离*/
}
.input2 {
border: 1px solid #1E1E1E; /* 输入框表框颜色*/
background-color: #F2F9FD; /* 输入框背景颜色*/
height: 30px; /*输入框高度*/
width: 80px; /*输入框宽度*/
}
</style>
<body>
<form action="updateServlet" method="post">
<table align="center">
<tr height="150dp">
<td></td>
</tr>
<tr>
<td colspan="2"><h1>用户更新</h1></td>
</tr>
<tr>
<td>ID:</td>
<td><input class="input1" type="text" name="id" readonly="readonly" value="<%=request.getAttribute("id") %>"/></td>
</tr>
<tr>
<td>用户名：</td>
<td><input class="input1" type="text" name="name" value="<%=request.getAttribute("name") %>"/></td>
</tr>
<tr>
<td>密码：</td>
<td><input class="input1" type="text" name="pwd" value="<%=request.getAttribute("pwd") %>"/></td>
</tr>
<tr align="center">
<td colspan="2"> <input class="input2" type="submit" value="更新"/></td>
</tr>
</table>
</form>
</body>
在该jsp页面，将要更新的数据进行修改，点击更新按钮后，数据将被发送到一个servlet页面进行处理，处理后会返回到登录成功时的servlet，通过该servlet进入登录成功时的页面。
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
request.setCharacterEncoding("utf-8");
String id = request.getParameter("id");
String name=request.getParameter("name");
String pwd=request.getParameter("pwd");
//获取到要更新的数据
Connection conn=DBUtil.getConn();
PreparedStatement ps=null;
ResultSet rs=null;
//更新语句
String sql="update acca set name=?, pwd=? where id=?";
try{
ps=conn.prepareStatement(sql);
ps.setString(1, name);
ps.setString(2, pwd);
ps.setInt(3,Integer.parseInt(id));
int r=ps.executeUpdate();
if(r>0){
//
response.sendRedirect("UserListServlet");
}else{
response.sendRedirect("UserListServlet");
}
}catch (SQLException e) {
e.printStackTrace();
}finally{
DBUtil.closeConn(conn, ps, rs);
}
}
如有错误的地方，请联系本人指正：QQ1609279469 备注CSDN 谢谢！